3" aluminum driveshaft

[Jeff Stout]

Originally Posted by Jim Caughlin

I have a 3" alum driveshaft that was built by Inland Empire, I cross the finishline at 9400 RPM and have relatively low HP. Interestingly, I was able to test duplicate steel (13#) and the alum one (10#) on back to back runs, zero performance difference. Actually, I can't say that I saw any noticeable performance improvement from any of the lightweight parts that I incorporated over the years (alum spool, lightened ring gear, gundrilled axles, etc), go figure...

One other note on going to a 3" alum driveshaft, don't forget about resonance / critical speed, it isn't purely a matter of strength. I believe there is a chart on the Mark Williams site that lists length vs RPM for different driveshafts.

Jim Caughlin
SS 6019

^^^ This. I found nothing in a BBC running high 9s bottom 10s and changed all the same things